feat(V2-1b): packages/core 추출 — 공유 타입/에러/채널/유틸 분리

packages/core (@d3ro/core) 신규 생성:
- types.ts, errors.ts, ipc-channels.ts, constants.ts (shared에서 이동)
- utils/meeting-markdown.ts, utils/markdown-to-docx.ts (main/utils에서 이동)
- subpath exports 정의 (./types, ./errors, ./ipc-channels, ./constants,
  ./utils/meeting-markdown, ./utils/markdown-to-docx)
- src/index.ts barrel export 추가
- docx를 core 자체 dependency로 선언

apps/desktop 연결:
- package.json에 @d3ro/core: '*' dep 추가
- tsconfig.node/web.json paths에 @d3ro/core/* 추가
- electron.vite.config.ts 3개 섹션 alias 추가 (main/preload/renderer)
- externalizeDepsPlugin exclude에 @d3ro/core (workspace 소스 번들 대상)
- vitest.config.ts alias 추가

일괄 치환 (79 파일, 167건):
- @shared/{types,errors,ipc-channels,constants} → @d3ro/core/*
- static/dynamic import + type expression import 모두 포함
- MeetingModeService.ts의 ../utils/* 상대 경로 → @d3ro/core/utils/*
- @shared/theme-vars는 V2-1c 범위로 남김 (WindowManager만 사용)

M1 수정 포함:
- electron.vite.config.ts의 resolve('src/shared') → resolve(__dirname, ...)
  CWD 독립적으로 동작하도록 견고화

검증:
- typecheck 통과
- build 통과 (main+preload+renderer)
- dev 런타임 → DB/핫키/Ollama 모두 정상, 기존 데이터 연속성 유지

apps/desktop/src/renderer/components/meeting/DocumentTab.tsx

@@ -9,7 +9,7 @@ import { ExportMenu } from './ExportMenu'
 import { PhysicalButton } from '../ds/PhysicalButton'
 import { d3roPalette, d3roTypo } from '../../theme'
 import { useI18n } from '../../i18n'
-import type { MeetingExportFormat } from '@shared/types'
+import type { MeetingExportFormat } from '@d3ro/core/types'
 
 interface DocumentTabDoc {
   id: string

apps/desktop/src/renderer/components/meeting/ExportMenu.tsx

@@ -7,7 +7,7 @@ import FileDownloadIcon from '@mui/icons-material/FileDownload'
 import { PhysicalButton } from '../ds/PhysicalButton'
 import { d3roPalette, d3roTypo, d3roFontMono, d3roRadius, d3roShadow } from '../../theme'
 import { useI18n } from '../../i18n'
-import type { MeetingExportFormat } from '@shared/types'
+import type { MeetingExportFormat } from '@d3ro/core/types'
 
 interface ExportMenuProps {
   onExport: (format: MeetingExportFormat) => void

apps/desktop/src/renderer/components/meeting/MeetingChatPanel.tsx

@@ -11,7 +11,7 @@ import { PhosphorText } from '../ds/PhosphorText'
 import { PhysicalButton } from '../ds/PhysicalButton'
 import { d3roPalette, d3roFontMono, d3roTypo, d3roShadow } from '../../theme'
 import { useI18n } from '../../i18n'
-import type { MeetingChatMessage } from '@shared/types'
+import type { MeetingChatMessage } from '@d3ro/core/types'
 
 interface MeetingChatPanelProps {
   sessionId: string

apps/desktop/src/renderer/components/meeting/MeetingDetailTabs.tsx

@@ -26,7 +26,7 @@ import type {
   MeetingDocument,
   MeetingDocTemplate,
   MeetingExportFormat,
-} from '@shared/types'
+} from '@d3ro/core/types'
 
 interface MeetingDetailTabsProps {
   detail: MeetingSessionDetail